Many kinds of removable band-type couplings for pipes exist in the art. It is noted that throughout the specification and claims, the term “pipe” encompasses any kind of generally cylindrical object, and the terms “clamp” and “coupling” are used interchangeably.
Pipeline leakage must be prevented for both economic and environmental reasons, depending on the nature of the fluid being transported. When needed repairs are inevitably carried out under field conditions, and in many situations there is a requirement that the flow of fluid in the pipeline may not be interrupted for any reason. Thus replacement of a faulty pipe joint is not an option.
Prior art seals are not capable of being used externally over an existing coupling or existing bell joint. Prior art seals lack the internal space needed if the repair seal is to be applied over and around an existing but leaking pipe joint. A further problem with many prior-art seals arises when the fluid being transported is under high pressure. This results in the seal lips being gradually pushed outwards, eventually leading to complete seal failure.
A solution to the above problems are split seal encapsulation pipe repair assemblies. The encapsulation seal assembly fits over existing bell-shaped joints, sleeve joints and the like, and seals the joint. The encapsulation seal assembly includes two metal half-rings that are bolted together at top and bottom flanges of the half-rings. Two elastomeric sealing half-rings are permanently attached to the inside of the two metal half-rings, and these sealing half-rings are clamped on both sides of the leak to stop the leak.
Another encapsulation seal assembly is described in U.S. Pat. No. 9,551,444. This assembly includes a band having an inner annular seal wrappable around a pipe. The band has opposing clamp members that are clamped together with tightening screws. Retaining elements are assembled in slots formed in the annular seal. The retaining elements have a retaining flap arranged to block outward migration of the annular seal element.